1. Field of the Invention
The present invention relates generally to a hybrid vehicle comprising an electric motor and an internal-combustion engine as driving sources for running.
2. Description of the Related Art
Conventionally, some vehicles comprising an internal-combustion engine as a driving source for running select a traveling mode which prioritizes fuel efficiency and run in this traveling mode when an amount of remaining fuel used in the internal-combustion engine becomes small. (For example, see Patent Literature 1.)
PATENT LITERATURE 1: Jpn. Pat. Appln. KOKAI Publication No. 2009-127548
The technology disclosed in Patent Literature 1 is technology to switch to the traveling mode which prioritizes fuel efficiency when the amount of the remaining fuel becomes small in the vehicle comprising the internal-combustion engine as a driving source for running. In this technology, if drive of the internal-combustion engine is stopped by decrease of the fuel, deceleration or deterioration of a driving feeling may occur.
In contrast, a hybrid electric vehicle comprising an electric motor and an internal-combustion engine as driving sources for running is conventionally under consideration. Such a hybrid electric vehicle has a series traveling mode for running only by the electric motor, and a parallel traveling mode using energy produced by the electric motor and the internal-combustion engine and using energy produced by the internal-combustion engine for generating electric power.
Even if the technology disclosed in Patent Literature 1 is applied to this type of hybrid vehicle, the deceleration or the deterioration of a driving feeling may occur in a state of running by the internal-combustion engine.